Optical disc capable of revealing preservation condition

Abstract

The present invention is to provide an optical disc which comprises a substrate and a multi-layer structure. The multi-layer structure is formed over the substrate, and at least one layer of the multi-layer structure contains an indicating material. Furthermore, the indicating material has a respective color changeable in response to permeation of oxygen or moisture into the layer containing the indicating material.

1 . An optical disc, comprising: 
 a substrate; and    a multi-layer structure formed over the substrate, at least one layer of the multi-layer structure containing an indicating material, and said indicating material having a respective color changeable in response to permeation of an oxygen or a moisture into the layer containing the indicating material.    
   
   
       2 . The optical disc of  claim 1 , wherein the indicating material is one selected from the group consisting of a Cobaltous Oxide (CoO), a Sodium diphenylaminesulfonate, a ferroin and their mixtures.  
   
   
       3 . The optical disc of  claim 2 , wherein the at least one layer containing the indicating material comprises a surface layer of the multi-layer structure.  
   
   
       4 . The optical disc of  claim 2 , wherein the at least one layer containing the indicating material comprises a recording layer of the multi-layer structure.  
   
   
       5 . The optical disc of  claim 1 , wherein the optical disc is configured to comply with a CD-R specification or a CD-RW specification.  
   
   
       6 . The optical disc of  claim 5 , wherein the surface of the optical disc has at least one transparent area for observing the change of color of said indicating material.  
   
   
       7 . The optical disc of  claim 6 , wherein the transparent area is located within an extreme inner periphery or without an extreme outer periphery of the optical disc.  
   
   
       8 . An optical disc, comprising: 
 a first substrate;    a multi-layer structure formed over the first substrate, at least one layer of the multi-layer structure containing an indicating material, and said indicating material having a respective color changeable in response to permeation of an oxygen or a moisture into the layer containing the indicating material; and    a second substrate, formed over the multi-layer structure.    
   
   
       9 . The optical disc of  claim 8 , wherein the indicating material is one selected from the group consisting of a Cobaltous Oxide (CoO), a Sodium diphenylaminesulfonate, a ferroin and their mixtures.  
   
   
       10 . The optical disc of  claim 9 , wherein the at least one layer containing the indicating material comprises a bonding layer of the multi-layer structure.  
   
   
       11 . The optical disc of  claim 9 , wherein the at least one layer containing the indicating material comprises a recording layer of the multi-layer structure.  
   
   
       12 . The optical disc of  claim 8 , wherein the optical disc is configured to comply with a DVD-R specification or a DVD+R specification.  
   
   
       13 . The optical disc of  claim 8 , wherein the optical disc is configured to comply with a DVD-RW.  
   
   
       14 . The optical disc of  claim 13 , wherein the surface of the optical disc has at least one transparent area for observing the change of color of said indicating material.  
   
   
       15 . The optical disc of  claim 14 , wherein the transparent area is located within an extreme inner periphery or without an extreme outer periphery of the optical disc.